Is it possible to sell excess energy back to the grid with V2G?

Yes, UK homeowners and small business owners who own electric vehicles (EVs) equipped with Vehicle-to-Grid (V2G) technology can sell excess energy stored in their EV batteries back to the electricity grid. This bidirectional charging system allows energy to flow both into the vehicle for charging and back out to the grid, improving energy use efficiency and offering financial benefits.

What is V2G and how does selling energy back to the grid work?

Vehicle-to-Grid (V2G) technology enables EV batteries to act like mobile energy storage units. When your EV is plugged in:

• It charges when electricity prices are low or when there is surplus renewable energy on the grid.
• It can discharge stored energy back to the grid during peak demand times when electricity prices are higher.

This process helps balance the grid by managing supply and demand and provides an opportunity for EV owners to earn money by selling excess electricity stored in their vehicle’s battery.

Real-world examples in the UK

• Octopus Energy’s PowerPack Tariff: One of the UK's largest energy suppliers launched a V2G tariff where customers get free EV charging in exchange for allowing control over when their vehicle charges or discharges. This enables owners to sell electricity back to the grid during high-price periods, potentially saving or making significant amounts of money—an average saving of over £850 per year has been estimated.

• Kaluza’s Domestic V2G Trial: This large-scale trial demonstrated that UK homeowners could earn up to £725 annually by participating, simply by keeping their cars plugged in when not in use. The system uses software to maximise earnings by optimising charging and discharging based on market prices and grid needs.

Benefits for UK homeowners and small businesses

• Financial savings and earnings: EV owners could save or earn hundreds of pounds annually by selling energy back to the grid.
• Supporting renewable energy: V2G helps use excess renewable energy more efficiently, reducing reliance on fossil fuels.
• Grid stability and resilience: Helps manage peak demand periods, reducing the need for expensive grid upgrades.
• Energy independence: Combined with home solar panels, V2G can enhance self-consumption of locally generated energy.

Practical advice for UK users interested in V2G

• Check vehicle compatibility: Only certain EV models support V2G; verify if your car and charging equipment are compatible.
• Install the right charger: A bidirectional charger is needed, which can be more expensive than standard chargers but prices are falling.
• Choose appropriate tariffs: Look for energy tariffs or providers offering V2G-friendly deals like Octopus Energy’s PowerPack.
• Consider battery impact: Frequent discharging can affect battery life, so assess usage patterns and warranty implications.
• Keep your EV plugged in: Earnings and grid support depend on your car being connected during idle times.

Key pros and cons

Pros	Cons
Earn money by selling energy back to grid	Higher upfront cost for bidirectional chargers
Reduce energy bills with smart charging	Compatible EVs and chargers are currently limited
Help balance the grid and support renewables	Potential battery wear concerns if not managed properly
Benefit from emerging tariffs and incentives	Requires flexibility in EV use and charging times

Common mistakes to avoid

• Assuming all EVs and chargers support V2G—confirm compatibility before purchasing.
• Not reviewing the terms and conditions of V2G tariffs regarding EV use restrictions.
• Disconnecting the vehicle too frequently, missing out on earning opportunities.
• Ignoring the impact of battery cycling on long-term battery health.
• Overlooking installation requirements and potential costs for bidirectional charging equipment.

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In summary, it is definitely possible and increasingly practical in the UK to sell excess energy back to the grid using V2G technology, especially with emerging tariffs and expanded trials proving its viability. For homeowners and small businesses, this means EVs not only save and earn money but also contribute actively to a more sustainable and efficient energy system.